874 Examination zf St. Pierre's Hjfotbejis 



dian as ourfelves : and alfo why our morning tides in winter 

 rife higher than thole of the evening, and why (he order of 

 oar tides changes every fix months; becaufe, the fun being 

 alternately towards both poles, the effect of the tides muft be 

 oppofitc, like the caufes which produce them. At the fol- 

 ftices the tides are lower than at any other fcafon of the year, 

 and thofe likewife are the feafons- when there is moll ice on, 

 the two poles, and confequently leaft water in the fea : the 

 reafon is obvious, the winter folftice is with us the feafon ot 

 the greateft cold ; of courfe there is the greateft poffible ac- 

 cumulation of ice on our pole and hemifphere. At the fouth 

 pole it is indeed the fummer folftice ; but little ice is then 

 melted, becaufe the acYron of the greateft heat is not felt 

 there as- with us, till the earth has an acquired heat fuper- 

 added to the fun's a&ion, which takes place the fix week* 

 following, the fummer folftice. 



At the equinoxes, on the contrary, we have the highefi^ 

 tides j and thefe are precifely the feafons when there is leaft 

 ice at the two poles, and of courfe the greateft quantity of 

 water in the ocean. At our autumnal equinox in September, 

 the greateft part of the ices of the north pole is melted, and 

 thofe of the fouth pole begin to diflblve. The tides in 

 March rife higher than thofe in September, becaufe it is the 

 end of fummer to the fouth pole, which contains much 

 more ice than ours, and confequently fends a greater mafs of 

 tvater to the ocean. 



I fhall fay nothing (he proceeds), of the intermittence of> 

 the polar effufions, which produce on our coaft two fluxes and 

 two refluxes nearly in the fame time that the fun, making 

 the circuit of the globe, alternately heats two continents an4 

 two oceans, that is, in the fpace of 04 hours, during which 

 his influence twice acts and is twice fufpended j nor fhall I 

 fpeak of the retardation, which is nearly 4 of an hour every 

 day, and which feems regulated by the different diameters of 

 the polar cupola of ice, whofe extremities, melted by the fun, 

 diminifh and retire from us everyday, and whofe effufions 

 muft confequently require more time to reach the line, and 

 to return from the line to us. Nor fhall I dwell on the other 

 relations thefe polar periods have to the phafes of the moon, 



efpecially 



